/**
 * Created with IntelliJ IDEA.
 * Description:
 * User: 26727
 * Date: 2024-05-10
 * Time: 22:12
 */
class Solution6 {
    public boolean isInterleave(String s1, String s2, String s3) {
        int m = s1.length(), n  = s2.length();
        if(m + n != s3.length()) {
            return false;
        }
        s1 = " " + s1;
        s2 = " " + s2;
        s3 = " " + s3;
        //创建dp
        boolean[][] dp = new boolean[m+1][n+1];
        //初始化

        dp[0][0] = true;
        for(int i = 1; i <= m; i++) {
            if(s1.charAt(i) == s3.charAt(i)) dp[i][0] = true;
            else break;
        }
        for(int j = 1; j <= n; j++) {
            if(s2.charAt(j) == s3.charAt(j)) dp[0][j] = true;
            else break;
        }
        //状态转移
        for(int i = 1; i <= m; i++) {
            for(int j = 1; j <= n; j++) {
                if((s1.charAt(i) == s3.charAt(i+j) && dp[i-1][j]) ||
                        (s2.charAt(j) == s3.charAt(i+j) && dp[i][j-1])) {
                    dp[i][j] = true;
                }
            }
        }
        return dp[m][n];
    }
}
